Nucleic acids, proteins and phytohormones have routinely been assigned key regulatory roles in plant signal transduction pathways. Our studies demonstrate a unique and previously undefined role for fatty acids (FA) as signaling molecules. We have shown that the monounsaturated FA, oleic acid (18:1), mediates defense signaling in Arabidopsis and soybean. Specifically, a reduction in the levels of 18:1 induces the expression of a variety of resistance (R) genes in plants. In turn, this global induction of R genes confers broad-spectrum disease resistance against multiple pathogens. This project aims to elucidate the molecular and biochemical mechanisms underlying the 18:1-derived regulation of R gene expression and defense activation in plants. This will be achieved by characterizing proteins that directly bind 18:1. The project would not only help elucidate this novel 18:1-mediated pathway, but will likely provide useful insights into networking between R gene and low 18:1-mediated signaling. Results obtained here could be applied to signaling networks in many other systems, since the underlying biochemical activities are conserved amongst a variety of plant species and 18:1 is an essential monounsaturated fatty acid in plants and animals alike.
Intellectual Merit. Characterization of the 18:1-regulated pathway will help elucidate novel, hitherto uninvestigated mechanisms of plant defense. This work will provide critical information about the regulatory role of fatty acids in addition to their traditional role as energy reservoirs. It could also redefine our current understanding of known defense signaling pathways as well as provide important insights into the complex networking between metabolic and defense signaling. Research findings from Arabidopsis will be applicable to less genetically tractable crop plants, and may help us to develop alternative disease controls that are less costly and less harmful to the environment and human health.
Broader Impacts. Critical insights into the complex networking between metabolic and defense pathways in plants are key to developing novel disease protection strategies. The information obtained here could potentially be applied for engineering broad-spectrum disease resistance in economically important crop plants. Therefore, knowledge obtained from this study will eventually increase crop productivity. Furthermore, 18:1 is also known to affect several vital physiological processes in mammalian systems. For example, 18:1 affects the contractile activity of heart and vascular smooth muscle cells, is the cause of pulmonary edema induced in adult respiratory stress syndrome, and is well known for its cancer protective abilities. Thus, understanding 18:1-derived signaling in plants is likely to provide insights into disease processes in humans as well. This research will incorporate training of undergraduate, graduate and postdoctoral students, and enhance the research infrastructure through sharing of ideas and materials. The investigators aim to foster a community of undergraduate students, particularly those from traditionally underrepresented groups, by including them as members of their scientific team. They also plan to integrate their research with the extension services available at the University of Kentucky to enhance awareness of the recent advances in crop resistance among farmers and agribusiness representatives.
